9165991 has 4 divisors (see below), whose sum is σ = 9174312. Its totient is φ = 9157672.

The previous prime is 9165977. The next prime is 9165997. The reversal of 9165991 is 1995619.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1995619 = 79 ⋅25261.

It is a cyclic number.

It is not a de Polignac number, because 9165991 - 2¹¹ = 9163943 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9165997) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2200 + ... + 4813.

It is an arithmetic number, because the mean of its divisors is an integer number (2293578).

Almost surely, 2^9165991 is an apocalyptic number.

9165991 is a deficient number, since it is larger than the sum of its proper divisors (8321).

9165991 is a wasteful number, since it uses less digits than its factorization.

9165991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8320.

The product of its digits is 21870, while the sum is 40.

The square root of 9165991 is about 3027.5387693637. The cubic root of 9165991 is about 209.2793970899.

The spelling of 9165991 in words is "nine million, one hundred sixty-five thousand, nine hundred ninety-one".